Electric meter.



No. 698,639. Patented Apr. 29, I902.

T. DUNCAN.

ELECTRIC METER. (Application filed Apr. 11, 1398. (No Model.) 4Sheets-Sheet I.

Fig. 1.

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MM $0M g Q W. wH/M W9"? No. 698,639. Patented Apr. 29, 1902.

T. DUNCAN.

ELEETRIG METER.

(Application filed Apr. 11. 1898.)

(No Model.) 4 SheetsSheet 2.

No. 698,639. v Patented Apr. 29, I902.

T. DUNCAN.

ELECTRIC METEFL (Application filed. Apr. 11, 1898.) (No Modei.) 4Sheets-Sheet 3.

Fig. 6.

(No Model.)

Patented Apr. 29, I902.

T. DUNCAN.

ELECTRIC METER.

(Application filed. Apr. 11, 1898 4 Sheets-Sheet 4,

was PEI Ens co, more flwwgm lmmw 3 QMWWWS n10, WASHiNOTQN n c NrrnnSTATES PATENT Orrice.

THOMAS DUNCAN, OF FORT WAYNE, INDIANA, ASSIGNOR TO THE SIEMENS dcIIALSKE ELECTRIC COMPANY OF AMERICA, OF CHICAGO, ILLINOIS, A

CORPORATION OF ILLINOIS.

ELECTRIC METER.

SPECIFICATION forming part Of Letters Patent NO. 698,639, dated April29, 1902.

Application filed April 11,1898- Serial No. 677,111. (No model.)

To all whom it 17260 concern:

Be it known that I, THOMAS DUNCAN, a citi- Zen of the United States,residing at Fort WVayne, in the county of Allen, in the State ofIndiana, have invented certain new and useful Improvements in ElectricMeters; and

I do hereby declare that the following is a full, clear, and exactdescription of the invention, which will enable others skilled in the :eart to which it appertains to make and use the same, reference being hadto the accompanying drawings, which form part of this specification.

My invention relates to improvementsin in- :5 tegrating motor-meters foralternating electric currents which are specially adapted for circuitsor loads containing inductance or lagging currents.

The object of my present invention is to provide in electric meters amethod of and means for producing a lag of the magnetism of thevolt-coil a quarter-period or ninety de grees behind the electromotiveforce of the circuit or system of supply to enable the me- 2 5 ter toaccurately measure loads containing self-induction or lagging currents.

My invention comprises in its preferred embodiment an electric meterhaving a magneto-electric drag for governing the speed,

whose retardation will be permanent in value and not easily affected orderanged by external magnetism, having such an arrangement of theretarding-magnets that a considerable change in retardation will beeffected by a slight variation in the position of the magnetsthemselves, and having a rate of rotation at all times proportional tothe actual electrical energy passing through the meter, whether it belamps,motors, or choke-coils which constitute the load.

Another object is to provide a simplicity of construction not liable tochange or derangement after adjustment for quadrature.

Similar reference-numerals in the accompanying drawings represent likeparts in the several views, in which- Figure 1 is a vertical centralsection of my improvement, showing the relative arrange mentof theenergizing-coils and retardingmagnets. Fig. 2 is a plan View of thesame, showing the manner of arranging the retarding-magnets whichembrace the adjacent portion of the armature and are adapted to adjustthe speed of rotation thereof. Fig. 3 is a similar view to Fig. 1,excepting that it shows an iron core arranged within the seriesfield-coil. Fig. at shows a movable contact-switch which is employed tocut in more or less of the convolutions of the volt-coil and aroundwhich the resistance 7 is shunted. Fig. 5 is a substantially similarView to Fig.

A and also shows an iron core arranged in the volt-coil. Fig. 6 showsthe manner of employing two series field-coils in my improvement. Fig. 7is a diagrammatic view showing the arrangement of the shunt-circuit ofthe meter. Figs. 8 and 9 show the phases of the currents in the severalcircuits of Fig. 7, more fully described hereinafter.

A description of my improvement with spe- 7o cial reference to Fig. 1 isas follows: The generator 9 is connected to the work-circuit 10 throughthe series field-coil 5 by means of the main leads 11 and 12. Arevoluble aluminium disk armature A is rigidly and concentricallymounted in any suitable manner upon a proper upright supporting-spindie3, provided with proper bearings at its extremities, and has a worm 2near its upper extremity adapted to mesh with the registering-train 1 inthe usual manner. The said series field-coil 5 is arranged and rigidlysupported adjacent to the lower face of said disk armature and ininductive relation thereto.

A shunt or volt coil 6 is arranged adjacent t0 the upper face of saidarmature and in inductive relation thereto. This volt-coil is connectedin parallel to the two main leads 11 and 12 by means of the wires 13 and14. The said series field-coil 5 is energized by 0 the current supplyingthe work-circuit 10, and its magnetic strength will vary directly as thecurrent in amperes passing through it. An impedance-coil 8 is connectedin series with the said volt-coil 6 to cause a lag of the 5 current inthis circuit approximating ninety degrees, and a non-inductiveresistance '7 is shunted around the terminals of the said voltcoil toassist in bringing the lag of the current through said coil up to ninetydegrees. When the work-circuit 10 is non-inductive, the currentsupplying it will be in step or phase with the electromotive force ofthe generator, and as the magnetism is in phase with its current we mayassume that the magnetism of the series field-coil 5 is also in stepwith the electromotive force of the generator.

The manner in which a lag of the magnetism of the volt-coil amounting toninety degrees or a quarter-period behind the generator or lineelectromotive force is produced by my present invention for the purposeof measuring inductive loads in which the current and magnetism of thework-circuit and the series coil lag behind the electromotive force ofthe generator is briefly stated as follows: \Vhen the impedance-coil isconnected in series with the volt-coil,the current through it will lagnearly ninety degrees; but for wellunderstood reasons the lag of thiscurrent must be somewhat less than ninety degrees. If the lag of thecurrent in the impedancecoil is, say, eighty-five degrees behind thecurrent through the volt-coil, the additional lag of five degreesnecessary to obtain quadrature is obtained by shunting the non-inductiveresistance 7 around the terminals of the volt-coil, then varying theresistance of the former until the current through the voltcoil is inthe desired quadrature. If the coil 6 and the resistance 7, which are inparallel to each other, have the same resistance and self-ind uction thecurrents through them will be in phase with each other and with thecurrent in the circuit-wires 13 and 14; but when the self-induction ofthe resistance 7 is decreased its current will be advanced in phase;ahead of the current in the said coil 6 and in the said circuit 13 and14, at the same time thecurrent through the coil 6 will have its lagincreased byan approximatelyequal number of degrees behind the currentin the said circuit or shunt connections 13 and 14. Ohviously,therefore, if the current in the circuits 13 and 14 be caused to lag,say, eightyfive degrees by means of the impedance-coil 8 and thevolt-coil 6 and by varying the resistance 7 until its current advancesin phase five degrees ahead of the current through the impedance-coil,which is eighty-five degrees, the current through the Volt-coil will bemade to lag five degrees. This gives approximately the current flowingthrough the circuit 13 and 14 a lag of eighty-five degrees behind thepressure of the mains 11 and 12 and eighty-five degrees less fivedegrees, oreighty degrees, for the current through the resistance 7, andit gives eighty-five degrees plus five degrees, or ninety degrees, forthe current through the volt-coil 6. As the current and magnetism ofsaid coil 6 are in phase with each other, the said magnetism actinginductively upon the disk armature and representing the electromotiveforce of the circuit 11 and 12 is also ninety degrees behind the saidpressure. Ob-

viously when there is no inductance in the work-circuit 10 the magnetismof the series coil 5 will be in phase With the line or generatorpressure and the magnetism of the coil 6 representing the saidline-pressure will lag ninety degrees behind the said pressure and theseries-coil magnetism.

Fig. 7 shows diagrammatically the arrangement of the several circuitscomprising the shunt or volt circuit of the meter.

Fig. 8 shows, by means of sine curves, the relative values and 'lags ofthe currents in the impedance-coil 8, volt-coil 6, and resistance 7 andtheir relation to the electromotiveforce curve of the circuit. Fig. 9shows the same result by employing the parallelogram of forces torepresent the electromotive forces by electromotive force, the current 7through the resistance 7, the current 6 through the volt-coil 6, and thecurrent 8 through the impedance-coil 8 and the Wires 13 and 14, as theresultant of the two currents 6 and 7. This difference of phase betweenthe volt-coil and the series or ampere coil produces alaterally-shifting magnetic field and adapted to actuate the armature.

The torque produced with a given current and pressure will vary as thesine of the angle between the magnetisms of the series and volt coilsand will at any instant represent the real or actual watts in theWork-circuit 10. 1

When the current through the series coil 5 lags behind theline-pressure, say, forty-five degrees, due to the introduction of anin-' ductive load in the circuit, the magnetism of the coil 5 will alsolag forty-five degrees, which gives it an advance of only forty-fivedegrees ahead of the magnetism of the. said coil 6 instead of ninetydegrees, as above described.

Assuming that the currentand pressure are the same in both cases, thereal watts will now be only .7071 of the original watts,when no lagexisted, or as the cosine of the angle of said lag, and as the torqueexerted upon the disk armature varies as the sine of the angle of lagbetween the flux of the series coil and the flux of the volt-coil theresultant torque will be just .7071 of the original torque, since thesine ofifortyfive degrees is .7071, or equal to the real watts and thetwo angles complementary. The retarding-magnets 17 are arranged uponboth sides of the disk armature and embracing the same, as shown in Fig.1, with their unlike poles facing each other. The retarding-magnets aresecured to the clamps 23 to permit the necessary adjustment thereof. Theclamps slide in suitable guidesin the casting 24, and when the properadjustment is made the said clamps are secured to said guides 24 bymeans of the set-screw 25 in the slot27 of the casting 24. The saidclamps and the magnets are adjusted by means of the screw 18, whoseinner end is properly secured in the portion 26 of the casting 24, andby rotating said screw 18 the clamps :23, with their correspondingmagnets, are horizontally adjusted. The speed of said armature isregulated bya horizontal adj ustment of said magnets toward or from eachother. By adjusting said magnets closer together more lines of forcefrom each magnet are attracted or short-circuited by the other, therebydiminishing the number of edective lines of force acting upon thearmature, and thus reducing the drag and permitting an increase of speedof. said armature. By withdrawing said magnets or further separatingthem less of this short-circuiting takes place and permits an increasednumber of lines of force from each magnet to act upon the armature,thereby increasing the dragging effect. This adjustment can readily beeffected by the set-screws 18 or other proper manner. These magnets mayalso be so adjusted that their magnetism will cut the disk armature atany desired point between its perimeter and its axis. The manner thusdescribed of arranging the said magnets with their unlike poles in closeproximity to each other, whereby a mutual short-circuiting takes placebetween them, has the advantage that each of said magnets acts as akeeper or preserver for the other and also greatly reduces thedetrimental effects of external magnetic influences upon the saidmagnets, thereby obtaining great permanency in the strength of themagnetsan essential feature to secure reliable efficiency in a meter. Ipreferably employ a single disk 4, which in this instance acts in adouble capacity, it being an armature and also acting as a retardingelement.

I do not wish, however, to be limited to a meter wherein the retardingelement and the armature are made in one part.

I do not hereby limit myself to the arrangement of the energizing-coilsherein shown and described, as my invention can be employed with equalfacility in any form of inductionwattmeter having either a cylindricalor other form of armature. I prefer to employ means, as the switch 20,for varying the nnm ber of effective turns of the coil 6 to secureadjustment more effectively.

My described arrangement of magnets may be indefinitely varied, and anydesired number maybe employed. If desired, these magnets may be employedto secure the necessary retardation byhaving them act upon a secondmetallic disk.

Having thus described my invention and the manner of employing the same,what I desire to secure by Letters Patent is- 1. In an electric meter, aretarding device consisting of a pair or plurality of pairs of permanentmagnets having the adjacent unlike poles of each pair arranged incooperative relation upon the same side of the revoluble disk armatureas shown, a revoluble metallic disk armature in inductive relation tosaid retarding device, and means for adjusting said magnets to vary thedensity of the flux through said revoluble armature.

2. In a meter, the combination with a current-winding, of a measuringelement actuated thereby, a retarding element movable with the measuringelement, and permanent magnets, the unlike poles of the permanentmagnets being opposed, each magnet offering a path for lines of forcedue to the other, the retarding element being interposed between thepoles of each magnet, the unlike opposed poles being upon the same sideof the retarding element, the current-winding serving to effect anincrease in the magnetization of one permanent magnet corresponding tothe decrease in the magnetization of the other per= manent magneteffected by said windin g, substantially as described.

3. In a meter, the combination with a current-winding, of a measuringelement actu v ated thereby, a retarding element movable with themeasuring element, permanent magnets, the unlike poles of the permanentmagnets being opposed, each magnet oifering a path for lines of forcedue to the other, the retarding element being interposed between thepoles of each magnet, the unlike opposed poles being upon the same sideof the retarding element, the current winding serving to effect anincrease in the magnetization of one permanent magnet corresponding tothe decrease in the magnetization of the-other permanent magnet effectedby said winding, and means for effecting relative adjustment of thepermanent magnets, substantially as described.

4. The combination with two field-coils, of

means for modifying the phases of the magnetic field produced by one ofthem,means in shunt to said last-named coil for further modifying thephase of its magnetic field, and means for changing the number of turnsof the last-named coil in action, whereby the relative effect of the twofield energizing-coils is changed, substantially as described.

5. The combination with two field-coils, of means in shunt of one ofsaid coils for modifying the phase of its magnetic field, and means forchanging the number of turns of the latter coil in action, whereby therelative efiect of the two field energizing-coils will be changed,substantially as described.

Signed by me at Fort WVayne, county of Allen, State of Indiana, this 8thday of April, A. D. 1898.

THOMAS DUNCAN.

Witnesses JOHN E. DALTON, HOMER V. CARPENTER.

